VMware vCenter Server Heartbeat - How to Identify and Remove Ghost NICs

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Summary

This Knowledge base article provides information about the occurrence of ghost NICs when performing a physical to virtual conversion or when recreating a virtual machine and re-attaching the original hard drive.


More Information

Sometimes after a Physical to Virtual conversion or after recreating a virtual machine and re-attaching the original hard drive, the drivers for the old physical NIC are still present and the physical NIC is still considered by Windows as a device on the machine.

This can create a problem in that the original NIC will be ‘hidden’ somewhere in the system configuration and you will be unable to assign the IP address to the new NIC because it is still bound to the old NIC.

Symptoms

When attempting to assign an IP address to the virtual machine NIC the following message is displayed

" The IP address x.x.x.x you have entered for this network adapter is already assigned to another adapter"

Cause

The drivers for the NIC from the physical machine are still present and this physical NIC is still considered by Windows as a device on the machine resulting in the original NIC being hidden in the system configuration. This prevents you from being able to assign an IP address to the new NIC because it is still bound to the old NIC.

Resolution

To identify if you have a ghost NIC present, navigate to the list of devices in Windows Device Manager. If the new NIC is listed as “Microsoft Virtual Machine Bus Network Adapter #2” and that no other NICs are present in your system, a ghost NIC is present. You will be unable to assign the correct IP address to the new NIC until the ghost NIC is removed.

To get remove a ghost NIC, perform the following steps:

  1. Click Start > Programs > Accessories > Command Prompt .
  2. Type the following command and press Enter:

    set devmgr_show_nonpresent_devices=1
  3. Type the following command, and press Enter:

    start devmgmt.msc

    Note: Ensure that you type devmgmt.msc in the same Command Prompt where you typed set devmgr_show_nonpresent_devices=1 . This is because the Set command is only effective in the environment of the Command Prompt you opened and its setting will be cleared when you close it.
  4. In the Device Manager click View > Show hidden devices .
  5. Expand Network adapters. The physical network cards are now visible and grayed out.
  6. Right-click on these NICs and click Uninstall .

At this point you can assign the IP address to the new virtual NIC.

Note: Setting the following registry key and then rebooting the virtual machine will show all non-present devices and minimize the process to remove ghost NICs.

System Key: [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment]
Value Name: DEVMGR_SHOW_NONPRESENT_DEVICES
Data Type: REG_SZ (String Value)
Value Data: (1 = show all hidden devices)


Applies To

VMware vCenter Server Heartbeat, all versions


Related Information

None

KBID-2585

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